function [acceleration_maf_x, acceleration_maf_y, sample_time] = acceleration_acquisition(filename, sample_interval)

class_num = 2;
[acceleration_x, acceleration_y, acceleration_z] = textread(filename, '%*s%d%*s%d%*s%d');
for n = 1 : length(acceleration_x) 
    if (rem(n, class_num) == 0)
        acceleration_maf_x(ceil(n/class_num)) = acceleration_x(n) * 0.000244;% convert the acceleration number of x axis to g unit
        acceleration_maf_y(ceil(n/class_num)) = acceleration_y(n) * 0.000244;% convert the acceleration number of y axis to g unit   
        sample_time(ceil(n/class_num)) = sample_interval * ceil(n/class_num);% sample_interval unit: s  sample_time unit: s  
    end
end

end